2- The address topman telegram account gave to OP was publicly posted in the forum. If it was LDL, Why would he give the same address to an account buyer? I guess he spent enough time in the forum to know that anyone can search for the address and check if this address was used in this forum. It's easy to find the address owner through Ninjastic.
It takes minimum six months to become a Sr. Member. Depending on activeness, it may take longer. LDL account seems familiar about Reputation and Meta sections. At least
ninjastic statistics proves it. He must know finished a used address is just matter of time.
If the address was given by real LDL say just by mistake, he would immediately delete the address and send another one. His excuse could be easier just by saying I gave you a wrong address, please send btc to this new address.